Gas anchor



INVENTOR 2 Sheets-Sheet 1 Howard CIPyZe Feb. 23, 1943. H. c. PYLE GASANCHOR Filed July 11. 1959 ATTORNEY.

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Feb. 23, 1943. H. c. PYLE GAS ANCHOR Filed July 11, 1939 2 Sheets-Sheet2 7amw .1

5 -IIIIIIIIZI -12: EFIZIZI 2- iiil witi. iuaililiiis IINVENTOR Howard C.Pyle ATTORNEY.

i! Al!!! Patented Feb. 23, 1943 GAS ANCHOR Howard C. Pyle, Glendale,Calif., assignmto Union Oil Company of California, Los Angeles, Calif.,a corporation of California Application July 11, 1939, Serial No.283,792 7 7 7 Claims.

This invention relates to improvements in the separation of liquid andgas mixture and speciflcally to the separation of oil and gas within apumping oil well by means known as a gas anchor" and is a continuationin part of my copending application Serial No. 216,086 filed June 27,1938, patented June 2, 1942, No. 2,285,169.

The primary object of this invention is to provide an apparatus forincreasing the volumetric efllciency of an oil well pump by eflectingseparation from the produced oil flowing into the well bore of asubstantial portion of the dispersed gases and dissolved gases presentin the oil in a state of supersaturation before it reaches the well pumpcylinder. Another object of the invention is to provide an improveddevice which will effectively separate oil'and gas and which can bereadily attached to the inlet of the conventional well pump cylinderlocated and supported by the tubing at or near the bottom of the well.Another object of the invention is to provide means of agitating theproduced 011 containing dissolved gas prior to its entrance into thepump cylinder whereby equilibrium is promoted and gas which is presentin solution in excess of saturation is caused to be liberated rapidlyfrom the solution and to be separated from the oil prior to the entranceof the oil into the pump cylinder. Another object of this invention isto provide means to'increase the inlet pressure of the fluid enteringthe pump to compensate for the drop in pressure at the inlet valves andpassages through the gas separation chamber whereby the volumetricefllciency is increased. It is also an object of the invention toimprove the gas separation from the liquid by providing means todischarge positively separated 7 gas from the gas separation zone.

With these objects in view this invention resides broadly in anapparatus for efiecting agitation of the produced gas-containing oil atthe bottom of a pumping well whereby gas is sepa rated therefrom priorto its entrance into the pump cylinder and whereby the volumetriceniciency of the pump is increased. The invention more specificallyresides in means for applying centrifugal force and agitation to the oilin a pumpingwell whereby gas is separated from the all prior to itsentrance into the pump cylinder. The invention also resides in anapparatus for increasing the inlet pressure of the liquid'entering thepump and to expel positively separated gas from the separator. These andother objects and features of novelty "will be evident hereafter.

The oil tubing In the drawings, which illustrate by way of illustrationpreferred embodiments of the invention and in which like numeralsdesignate similar parts throughout the several views;

Figure 1 is a partial cross-sectional elevation of the gas anchorseparator mechanism in place in the perforated casing in the welltogether with a partial cross-sectional view of a reciprocating type ofwell pump to which it is adapted.

Figure 2 is a lower extension oi! the apparatus shown in cross-sectionin Figure l.

Figure 3 is a cross-section taken at line 3-3 of Figure 2 through thegas separation chamber.

Figures 4 and 5 illustrate a partial cross-sectional elevation of anoptional adaptation of the gas anchor to an electrically driven turbinetype of oil well pump.

Referring to Figures 1, 2 and 3 of the drawings, I0 is an oil string,casing or liner carrying a perforated section Ii opposite the producingformation and adapted to be suspended from a casing in the well, as isconventional practice. It is suspended in the well and within the casingfrom the casing head in the conventional manner and may extend downwardinto the well as shown in the drawings to a point adjacent the producingzone within the perforated casing H. At the lower end of the tubing isattached a pump barrel I5 in which the pump plunger i8 is operated bymeans of suitable sucker rods I! extending to the top of the well andadapted to be reciprocated by means Extending from the lower end ofbarrel and communicating with the valve and the pump barrel inlet is asurge chamber 25 formed by a downwardly extending section of tubing 26supported at the top and making gas tight connection with the lower endof said pump barrel. The surge chamber 25 is thus in the iorm of anannular space in which a cushioning body of gas may be entrapped above aliquid level as shown at 21.

Also extending from the lower end of the pump is a cylindrical casing 28concentrically surrounding the surge chamber 25 and the surge chambertubing 28 forming between said surge chamber the pump standing wall 28and said cylindrical casing 28, an annular passageway 29 communicatingat the upper end through ducts and at the lower end through ducts 32 andII 30 and it with the pump inlet with the discharge of a multi-stagecentrifugal booster pump 35. The said booster pump 35 comprises, by wayof illustration here, two centrifugal stages of which 36 and 31 are thefirst and second stage impellers respectively mounted upon and keyed toa hollow rotatable shaft 38 which in turn is connected at its lower endwith a prime mover, described hereinafter. The suction or inlet end ofthe booster pump 35 is connected by means of ducts 39 and 48 and throughthe annular space 4| to the top of a gas separating chamber 42.

The gas separating chamber 42 comprises a tubular casing 44 downwardlyextending from the booster pump body and containing a rotor 45pcsitioned therein. The rotor 45 comprises a plurality of vanes 41radiallyi extending from the hollow shaft 38, the whole being rotatablewith slight clearance at the edges of said vanes within the insidesurface of the cylindrical gas separating chamber 44. The hollow shaft.38 is rotatably mounted and supported at the top upon a ball bearing 49and at the lower end in plain journal bearing 58 of enlarged diameter.The shaft 38 passes through stufllng boxes 52 and 53. The lower end ofshaft 38 is coupled by means of a rod 55 through universal joints 58 and51 to the prime mover 58 by means of which the whole shaft upon whichthe vanes 41 are mounted may be rapidly rotated.

The prime mover, by way of illustration here, comprises a fluid operatedrotary motor having helically grooved stator 59 and rotor 68. Thisturbine may be constructed in accordance with the disclosures of U. S.patents to Moineau, Numbers 1,892,217 and 2,028,401.

Pressure fluid for the operation of the rotary motor is obtained fromthe tubing I4 at point 82 above the pump barrel whereby it is maintainedunder the static pressure of the fluid column extending upwardly to thetop of the well. A. screen 83 is provided at the fluid pressureconnection 82 at the tubing to exclude sand or other foreign particleswhich may be entrained in the produced liquid from reaching the fluidoperated motor. The pressure fluid withdrawn from the tubing I4 at 62 isfree to flow downward through the annular space 65 surrounding pumpbarrel through the ducts 68 and 81 and the central tubing passageway 58to the top 88 of the hollow shaft and thence through the hollow shaft tothe side outlet 18 into the chamber 1! formed in the casing between thestuffing box 53 and the shaft supporting bearing 58. From the saidchamber ii the pressure fluid may flow through the ducts 13 and 14 tothe chamber 15 which communicates with the upper inlet end of the rotarymotor 58. The exhaust from the motor 58 may pass out to the space in theperforated casing through a plurality of exhaust ports 18.

A plurality of inlet ports 18 are provided to allow liquid in the wellto pass into the gas separating chamber 42 through the annular passage13 formed between the hollow shaft 38 and an annular baiiie 88.

Extending from the lower portion of the booster pump body is shown aconcentrically disposed sleeve 82 forming an inner annular space aboutthe shaft 38 and an outer concentric annular space 84 inside of thecasing 44. The inner annular space 83 is vented to the outside of thegas anchor through a port 85 and this chamber contains a pair ofimpellers 85 and 81 adapted to force the fluid entrapped in said annularspace upward and outward through said vent 85.

The outer annular space 84 is connected to the suction inlet of thebooster pump 35 through the before-mentioned ducts 38 and 48.

The apparatus illustrated in Figures 4 and is similar to thatillustrated in Figures 1, 2 and 3 except that the gas anchor apparatusis shown by way of illustration as adapted to be connected to an oilwell pump of the centrifugalor rotary pump type and instead of employinga pressure fluid operated motor, as shown at 58 in Figure 2,

as a prime mover for the rotation of the gas separation apparatus,rotation of these parts is accomplished by means of a suitableconnection with a lower shaft extension from the drive of 5 thecentrifugal or rotary well pump which is shown as extending from thelower end of the electrical pump unit through packer 9| in Figure 5.

The centrifugal or rotary well pump to which the apparatus of thisinvention is adapted to be connected, may be of any suitable well knowndesign, such as, for example, the Reda electrical centrifugal oil wellpump manufactured by the Reda Pump Company of Bartlesville, Oklahoma, asillustrated, in part, in Figure 4, employing an electrical motor drivingunit 83, a protector unit 84 which seals the motor from the pump and acentrifugal pump unit 95. The suction inlet to the electrically drivencentrifugal pump is shown at 96 covered by strainer grating 38.

Communication between the discharge of the booster pump and the suctioninlet 96 of. the

said centrifugal pump 85 is provided through annular space 89 formedbetween the electrically 35 driven well pump and a tubular cover I88.

As stated above,-a shaft 88 extending from the free end of the electricdrive motor 93 makes connection by means of suitable coupling at [M withthe top of the solid shaft I82 upon which the booster pump impellers 38and 31, the. gas separator rotor vanes 41 and the impeller blades 85 and81 are mounted. The lower end of shaft I82 is rotatably supported inbearing I83.

Fluid inlet to the gas separating chamber 42 is provided by means of aplurality of ports 18 as gas separating chamber is provided at 85 as inFigure 1.

The discharge from the electrically driven centrifugal well pump 85 isconnected to the lower end of the well tubing I4 at I85 in theconventional manner. Electrical connection is made to 'the electricmotor drive 93 by means of electrical conductor as shown in part at I861The electrical conductor I88 extends to the top of the well through theannular space between the pump housing and the liner I8 and makes coection with a suitable source of electric. power as is conventionalinstallation practice of pumps of this type.

The operation of the apparatus of Figures 1, 2 and 3 is asfollows: Oilunder the force of gravity, or by the residual expulsive force of gas orwater, flows from the surrounding formation through the perforatedcasing II and accumulates in sufficient quantity within the casing toflow through the inlet ports 18 and through annular space 18 surroundingthe shaft 38 into the gas separating chamber 42 within the enclosingshell 44. Oil under the pressure of the fluid head accumulated in thecasing continues its flow upward through the gas separator 42 andthrough the outer annular passage 4! and through the inlet ducts 39 and48 to the suction of the booster pump 35. Ordinarily, there is alsosufficient in Figure 2. A vent for separated gas from the,

fluid head of accumulated oil in the casing to cause the oil to flowupward through the passages in the impellers 31 and 38 of the boosterpump through the ducts 32 and 33 and on through ducts 30 and 3| andfinally through the standing valve 2| into the reciprocating pump barrelI5.

Under normal operating conditions, the pump lunger l6 carrying thetraveling valve 20 is reciprocated within the pump barrel l5, thusdrawing oil through the standing valve 2| and forcing it upward throughthe traveling valve 20 into the tubing l4 and thus maintaining an upwardmoving column of oil above the pump plunger 20 and extending to the topof the well. The oil pressure in the tubing [4 near the bottom of thewell and at the point 62 above the pump barrel is thus under a highfluid pressure head which is dependent upon the depth of the well, thedensity of the fluid and the back pressure upon the delivery line at thetop of the well. At this point 62 in the oil tubing above the pump,pressure oil is withdrawn through the screen 63 into the annular passage65 formed between the outside surface of the pump barrel l5 and thesurrounding casing through ducts 66, 61 and 68 through the hollow shaft38 and out through the side opening in said hollow shaft into thechamber 1| where the oil accumulates under the tubing pressure head.From the chamber H the pressure oil continues downward through the ductsl3 and 14 to the inlet 15 leading to the fluid operated rotary motor 58.The pressure oil from the rotary motor 58 is discharged through theports 76 into the accumulated fluid in the casing.

The passage of the pressure fluid through the motor 58 causes the rotor68 to rotate rapidly about its longitudinal axis. This rotation of therotor 68 is communicated through a universal joint 51 to the shaft 55and thence through the universal joint 56 to the hollow shaft 38 uponwhich the gas separator rotor vanes 41, the separated gas impellerblades 86 and 81 and the booster pump impellers 36 and 31 are carried.The pressure available for operating the said motor 58 is thedifferential between the tubing pressure at 62 and the bottom holepressure at the level of the turbine discharge ports 76 and thisdifferential pressure in the case of a low pressure formation and amoderately deep well may range from 1,000 to 3,000 pounds per squareinch. The differential pressure actually applied in the motor 58 may beadjusted by any suitable means such as a throttle valve or byrestricting the size of the ducts 66 and 67 through which the pressureoil passes. Under average operating conditions the rotary motor 58 andthe gas separator 46 carrying the blades 41 may be operated at a speedranging between approximately 1,000 and 4,000 revolutions per minute.

The oil containing dissolved and entrained gas which enters the gasseparator chamber 42, as hereinbefore described, is thus imparted rapidrotational movement by means of the rotor blades 41 as the mixturepasses upward toward the centrifugal booster pump 35. Under the effectof the agitation and the centrifugal force imparted to the oil-gasmixture by its rotation in the gas separator chamber 42, a substantialamount of the supersaturated gas is caused to be released from solutionand the thus released and entrained gas under the influence of the saidcentrifugal force, the said gas being of greatly different specificgravity than the oil from which it is thus separated, is forced towardthe center of the separating chamber and into a region immediatelysurrounding the rotor shaft 38. The separated gas then passes upwardalong the sur- 5 face of the shaft 38 parallel with the general flow ofthe oil until it is entrapped within the inner annular space 83 and fromthere, together with a quantity of oil is exhausted with the aid of theimpellers 86 and 81 from the apparatus 10 through the gas vent 85. Thesaid impellers 86 and 81 under rapid rotation upon the shaft 38 insurethe positive discharge of the gas-oil mixture accumulated in the annularspace 83, outward through the gas vent 85 into the annular 15 spacesurrounding the gas anchor and within the casing.

The oil from which the gas has thus been removed flows upward into theouter annular space 4| and thence through the ducts 39 and 40 to thesuction of the booster pump 35. The relatively gas-free oil thusreaching the centrifugal booster pump 35 is forced upward with theincreased pressure through the ducts in and 33 and into the surgechamber 25. The centinugal booster pump may be constructed with anysuitable number of stages, it being generally oesirable to provide asufficient boost or increase in oil pressure at this point to overcomefriction losses throughout the passages through the gas anchor and todeliver the oil into the reciprocating pump barrel at, or preferablyslightly above, the fluid head of the accumulated 011 in the casingsurrounding the pump at this point.

The suction pressure to the inlet of the well pump is thus maintainedequal to or preierably slightly higher than that which it would be ifmaking direct connection with the accumulated fluid in the well.

The oil delivered through ducts 32 and 33 to the surge chamber 25 risestherein to a liquid level as shown at 21 against the pressure ofaccumulated and entrapped gas in the annular space 25 and continues toflow upward through the annular space 29 and through the ducts 3d and 3|and through standing valve 2| to the pump barrel under the combinedfluid pressure of the accumulated oil in the casing and the dischargepressure of the centrirugal booster pump 35. In apparatus such as thatillustrated m Figure l employing a reciprocating plunger pump, the fluidinlet to the pump barrel will necessarily be intermittent. This requiresthat the oil supplied to the pump barrel l5 through the standing valve2| be intermittent and of suificient pressure and volume to fill thepump barrel on each upward stroke of the plunger without detrimentaldrop in pressure thereof. It is the purpose of the before-mentionedsurge chamber 25 to supply these necessary surges of oil to the suctionof the pump and this is accomplished in the surge chamber byintermittent lowering of the liquid level 2'! under the force of thecompressed gas entrapped in the annular space 25, the expansion of gasin the annular space 25 being of sufficient volume to displace therequired amount of oil from the surge chamber to supply the variationsin the intermittent demand of the reciprocating pump.

The operation of the apparatus of Figures 4 and 5 is as follows: Theaccumulated fluid in the casing ll enters the gas separating chamber 42by way of the inlet ports 18 and annular space 19. 42 as describedhereinbefore and 7 arated gas vented through 85.

The separation of oil and gas is eifected in the thus sep- The oil fromwhich the gas is separated passes upward in the gas separating chamber42 through the annular space 4| and through the ducts l8 and 40 to theinlet of the centrifugal booster pump 35. From the centrifugal boosterpump 30 the oil continues upward through ducts 32 and Il and through theannular space 90 inside of the enclosing casing I00 to the suction inlet00 of the centrifugal or rotary well pump 85 from which it is in turndischarged under pressure into the tubing I4 which extends to the top ofthe well. The shaft I02 upon which the gas separator rotor vanes 41, thegas discharge impellers 06 and t1 and the booster pump impellers 30 and31 are mounted, is rotated by means of the electric motor drive 08through a shaft extension 00 therefrom to which it is coupled at IOI.

It is to be noted that the gas separator, comprising the chamber 44 andthe rotor blades 41, in itself operates in a degree as a centrifugalpump. The annular baille I04 serves to confine the oil from which gashas been separated, under pressure over the inside surface of saidcylinder -44 and thus the oil withdrawn from the gas separating chamberthrough the annular space H is under slightly increased pressure overthat entering the chamber through the annular opening 10 immediatelysurrounding the shaft I02. The gas separator and the booster pump 35thus both combine to increase the inlet pressure to the centrifugal pump93.

The rotor vanes 41 may be varied somewhat in design. For example, therotor blades or vanes instead of extending radially from a shaft 24 mayextend at a slight angle therefrom or the rotor blades may be spirallyarranged around the shaft in such a manner as to further aid in liftingthe fluid from the inlet I9 toward the top of the gas separatingchamber.

It is to be understood that the foregoing is illustrative of but oneapparatus and that the invention is not limited thereby but may includeany apparatus which accomplishes the same within the scope of theinvention.

I claim:

lr-In a pumping well, the combination of a well tubing, a pump connectedat the lower end of said tubing, 9. gas separating chamber connectingwith the inlet of said pump and communicating with the fluid inthe well,means in said chamher to separate liquid and gas. and means toforcefully expel separated fluid from said chamber, said means to expelthe separated fluid from said chamber comprising a plurality ofrotatable blades.

2. In a pumping well the combination of a well tubing, a pump connectedat the lower end of said tubing, means to increase the inlet pressure ofliquid entering said pump and a surge chamber intermediate said pumpinlet and said pressure increasing means.

3. In a pumping well the combination of a pump, a gas separating chambercommunicating with the inlet of said pump, means intermediate saidchamber and said pump inlet to increase the inlet pressure of fluidentering said pump from said chamber and a surge chamber intermediatesaid pump inlet and said means to increase the inlet pressure.

4. In a pumping well the combination of a pump connected at the lowerend of said tubing, a gas separating chamber connecting with the inletof said pump and communicating with the fluid in the well, and a surgechamber intermedi-; ate said pump inlet and said gas separating:chamber,

5. In a pumping well the combination of a pump connected at the lowerend of said tubing, a gas separating chamber connecting with the inletof said pump and communicating with the fluid in the well, means in saidchamber to separate liquid and gas and means to forcefully expel Vseparated gas from said chamber, means intermediate said gas separatingchamber and saidpump inlet to increase the inlet pressure of fluid fromsaid chamber and entering said pump, and means intermediate said inletpressure increasing means and said pump inlet to equalize pump inletsurges in said liquid entering said pump.

6. Apparatus according to claim 5 in which the means to increase theinlet pressure to the pump comprises a centrifugal pump and meansassociated therewith to rotate said pump.

7. Apparatus according to claim 5 in which the means to increase theinlet pressure to the pump comprises a booster pump driven by pressurefluid withdrawn from the well tubing.

HOWARDC. PYLE.

